List of the strongholds or dar al-hijra of the Order of Assassins in Persia (Iran) and Syria.
Most of the Persian Ismaili castles were in the Alborz mountains, in the regions of Daylaman (particularly, in Alamut and Rudbar; north of modern-day Qazvin) and Quhistan (south of Khurasan), as well as in Qumis. Most of the Syrian Ismaili castles were in Jabal Bahra' (Syrian Coastal Mountain Range).
The Nizari state (the Alamut state) was a Nizari Isma'ili Shia state founded by Hassan-i Sabbah after he took control of the Alamut Castle in 1090 AD, which marked the beginning of an era of Ismailism known as the "Alamut period". Their people were also known as the Assassins or Hashashins.
The state consisted of a nexus of strongholds throughout Persia and the Levant, with their territories being surrounded by huge swathes of hostile as well as crusader territory. It was formed as a result of a religious and political movement of the minority Nizari sect supported by the anti-Seljuk population. Being heavily outnumbered, the Nizaris resisted adversaries by employing strategic, self-sufficient fortresses and the use of unconventional tactics, notably assassination of important adversaries and psychological warfare. They also had a strong sense of community as well as total obedience to their leader.
Maymūn-Diz (Persian: میمون دز) was a major fortress of the Nizari Ismailis of the Alamut Period described in historical records. It has been variously identified with the Alamut Castle, Navizar Shah Castle, Shirkuh Castle, Shahrak Castle, and Shams Kalayeh Cave. Recently, Enayatollah Majidi located it on top of Mount Shatan (کوه شاتان Kūh-e Shātān; 36°28′34″N 50°36′25″E / 36.4762463°N 50.6069645°E) near Khoshk Chal.
The fortress was surrendered by Imam Rukn al-Din Khurshah, who was residing there, to the invading Mongols under Hulagu Khan and was subsequently demolished. This was followed by surrender of Alamut and almost all other strongholds and the disestablishment of the Nizari state.
Lambsar (Persian: لمبسر, also pronounced Lamsar), Lamasar, Lambasar, Lambesar (لمبه سر) or Lomasar (لمسر) was probably the largest and the most fortified of the Ismaili castles. The fortress is located in the central Alborz mountains, south of the Caspian Sea, about 120 km from present-day Tehran, Iran. Lambsar is to the northeast of Razmian village (the central district of Rudbar e Shahrestan).
Kiya Buzurg Ummid (died 1138) captured the castle from Rasamuj and rebuilt it into a major stronghold using local labour. He was appointed by Hassan-i Sabbah (died 1124) as its governor.